The present application relates to biosensors for use in medical and environmental monitoring. More particularly, the present application relates to a biosensor calibration structure that includes at least two electrode structures in which at least one of the electrode structures has a non-random nanopattern on the sensing surface which provides a different sensing surface area than at least one other electrode structure. The present application also relates to a calibration method that employs the biosensor calibration structure of the present application.
Biosensors with enhanced signal and sensitivity are essential to provide reliable data for both medical and environmental monitoring. Such biosensors are especially needed for areas related to food and water supply security as well as the healthcare industry. For healthcare, glucose sensors comprise a significant portion of the existing biosensor market. Platinum (Pt) is commonly used as a working electrode in glucose sensors, and platinum has demonstrated biocompatibility. External electrochemical sensors (so-called “Test-Strips”) are commonly used. However, limitations exist on the accuracy and applicability of test strip sensors.
In vivo glucose sensors, which are implanted into a human body, can be used to continuously monitor blood sugar. However, the foreign body response restricts the functionality of in vivo biosensors. Moreover, the foreign body response can reduce the sensor signal output over time. In some applications, the foreign body response may even reject the biosensor from the human body.
For biosensors used in vivo or in other environments in which sensor stability could be at risk, effective methods of real-time sensor calibration are essential to provide reliable sensor outputs that can be trusted for decision making. For example, as in vivo sensor signal degrades to encapsulation as part of the foreign body response, validating the calibration accuracy becomes more of a challenge. In order to improve sensor calibration accuracy, commercial manufactures of in vivo glucose sensors are shifting their calibration strategies to use multiple electrodes of a same material or a different material as a means for calibration. Although such techniques improve, to some degree, the sensor accuracy and useful lifetime, the formation of multiple electrodes (specifically of different materials) is time consuming and increases the cost associated with the production process. There is thus a need to provide a structure that can be used in biosensor calibration that has enhanced accuracy, increased useful lifetime, and is cost efficient to manufacture.